A variety of items are marketed enclosed within. flexible bags or bag constructions. Among other things, such constructions can generally operate to: protect the enclosed item(s); retain a plurality of items in close association with one another; facilitate storage and handling; facilitate access to a portion of a stored quantity; and/or to inhibit contamination (and maintain freshness) of stored material. A variety of bag designs have been used, for such purposes.
In some instances, items stored within the bag construction are not completely stable, after the construction is sealed closed. For example, at a food processing/packaging plant materials such as coffee beans may be packaged (sealed) within such bag constructions, while hot. As materials such as coffee beans cool, gases are given off. These gases will expand the flexible bag construction taut, and eventually rupture it, unless vented.
To maintain integrity of the bag construction under such circumstances, vented bag arrangements have been developed. A frequently used general type of construction is one which involves an aperture or pore in a side wall of the bag construction, which is covered by a porous filter. As gas pressures build up within the sealed bag arrangement, the gases can pass outwardly through the vented pore and filter, to reestablish equilibrium of pressure between the interior and exterior of the bag. One commercially available filter for such use is the Bosch filter available from Robert Bosch Corporation. This filter arrangement generally comprises a piece of porous polymer material including portions having adhesive thereon, selectively positionable over a pore in the bag.
Conventional vented flexible bag arrangements for containing materials such as coffee have not been completely satisfactory in function. Reasons for this include the following: such constructions have not, in general, been conveniently constructed for ease of opening and resealing; the position of the vent or filter has not been completely desirable for maintenance of integrity during shelf life and use; and, the position of gas vents or filters in such arrangements have not been fully satisfactory with respect to potential interference with the operation thereof by material received within the bag, during use.
A better understanding of conventional arrangements can be obtained from consideration of the conventional arrangement illustrated in FIGS. 1 and 2. In FIG. 1 there is depicted, in perspective, a conventional, vented, flexible bag arrangement 1 having material 2 (such as coffee beans 3) stored therein. Arrangement 1 has first and second closed ends 5 and 6 and opposite sides 7 and 8. End 6 is preferably relatively permanently closed, by staples, adhesive or the like. End 5 is also closed (at the packaging plant) by means such as staples and/or adhesive; however it is opened (by the consumer or user) for access to an interior, to remove coffee 3 therefrom. In use, end 5 is reclosed by rolling that end of the bag up, and clipping, clamping, taping or otherwise securing the rolled up end in a tightly coiled configuration. As arrangement 1 is further depleted of its contents, during further use, end 5 is further rolled and compressed toward end 6. Reasons why this type of closure has been preferred include the fact that to maintain material 2 within arrangement 1 as fresh as reasonably possible, it is generally desirable to leave as little air in the arrangement 1, during storage, as easily manageable.
Still referring to FIG. 1, on an upper surface 10 of arrangement 1 a vent system or arrangement 15 is positioned. Vent arrangement 15 comprises a porous polymer filter arrangement or member 16 positioned over a pore 17. Pore 17 extends through surface 10, into fluid flow communication with an interior 18 of arrangement 1. Gas pressure build-up within arrangement 1, then, is vented by passage of the gases through porous filter member 16. The filter member 16 is selected, however, so that solid particles and the like do not pass there through. Thus, the contents of the bag do not leak outwardly. Also, preferably member 16 is selected so that it acts as a barrier to microorganism and moisture passage into the bag 1, to maintain freshness.
In a typical use, arrangement 1 is constructed with one open end (for example end 5) and is filled with material 2 to be stored, while material 2 is still in a hot state. The open end (end 5 in the example) is then sealed closed, and as the material cools, gases are given off. The gases build up pressure within arrangement 1 and are vented through pore 17 and filter member 16.
When the arrangement is ultimately obtained by a consumer, end 5 is opened, as necessary, for removal of material stored therein. As described above, end 5 is reclosed by collapsing, folding or rolling it toward end 6, and is maintained closed by means such as a retainer, clamp or tape. This practice is repeated, until the contents are completely used.
Typical operation of the arrangement 1 as just described, involves at least two potential problems. First, as end 5 is reopened and reclosed during use by the consumer, eventually the consumer will collapse or roll end 5 past vented arrangement 15. This poses little problem with respect to the required operation of vent arrangement 15, since its purpose will generally have been served prior to the consumer even obtaining the arrangement. However, a potential problem is nevertheless presented. In particular, vent arrangement 15 represents a portion of the overall construction 1 in which, as a result of the pore 17 and the filter member 16, a site of potential failure is presented. For example, in general, conventional arrangements utilized as a filter member 16, are not as flexible as materials used as the side walls, i.e. surface 10, of typical bag constructions 1. If the vent arrangement 15 resists coiling or collapse during the folding/rolling process involving end 5, the vent arrangement 15 or the construction 1 may tear or rupture, leading to a failure in the integrity of a side wall of arrangement 1. Thus, inconvenient spills, etc., may occur. Further, loss of freshness, due to loss of integrity of the closed system, may result. Similar problems would occur if instead of rapture, separation of the filter member 16 from the construction 1 occurred.
Another potential problem is presented from the location of arrangement 15. In particular, its position is such that when arrangement 1 is filled during packaging, solid material is present within arrangement 1, directly adjacent vent arrangement 15. Such solid material may interfere with free flow of gases through the vent arrangement 15. For example, prior to cooling and releasing of gases, small particles (i.e. dust) within the stored material 2 may block pore 17 and/or filter 16, so that when the gases are released from the stored material, they are not as readily vented from the bag arrangement 1.
Another potential problem with the arrangement of FIG. 1 is that it is not especially convenient for the consumer to use, from the point of view of opening and reclosing. For some consumers it may be inconvenient to perform the ritual of rolling the end 5 of arrangement 1, between uses, and finding a method of maintaining same closed, for example, through use of tape or clamps. While some conventional arrangements include wires therein (or tape thereon) to facilitate the process, these may be relatively expensive to provide and/or inconvenient to use. Further, they may represent yet another site of potential failure in the construction or maintenance of closure.
To further facilitate understanding of the arrangement of FIG. 1, attention is directed to FIG. 2. FIG. 2 is a perspective view of a panel 20 having a vent arrangement 21 therein, from which an arrangement such as that of FIG. 1 can be formed. That is, arrangement 1 of FIG. 1 is formed from a single panel, and thus provides for a single seam. Formation of the seam will be understood by reference to FIG. 2, wherein panel 20 is shown folded to form upper surface 25 opposite side gussets 26 and 27, and back panels 28 and 29. In practice, a tube arrangement (with a single longitudinal seam) is formed by joining back panels 28 and 29 to one another. The tube arrangement is then closed along one end, for example end 30, prior to filling with material. After filling with material, the opposite end 31 is then closed, the result being an arrangement similar to that shown in FIG. 1. In some instances the filter member 33 of the vent arrangement 21 is applied after formation of the bag, rather than before.